How about a compromise? Put aside part of the money to save for a new machine, then use the rest to pay your bills. Every paycheck period, pay yourself first--put some money into your sewing machine fund. You'll have enough before you know it, and you won't feel guilty and be in debt because you didn't pay your bills.
There just never seems to be enough money to go around, but if you're willing to compromise, you can still find a way to get what you need AND what you want--just not all at once!